Senior C# .NET Developer — Desktop Applications & Backend Systems | Long-Term Contract

We’re a growing software company looking for an experienced C# .NET Developer to join our engineering team on a long-term hourly basis. We build and maintain business applications used by real customers and internal teams. We’re looking for someone who can take ownership of existing systems, develop new features, improve performance, and help us continuously improve our products. You’ll work across desktop applications, backend services, APIs, and database-driven solutions using the Microsoft technology ecosystem. If you enjoy solving complex technical problems, working with mature codebases, and delivering reliable software that people depend on every day, we’d love to hear from you. What you’ll do - Develop and maintain C#/.NET applications for business workflows - Build and improve Windows desktop applications using WPF and WinForms - Create and maintain backend services with ASP.NET Core - Design and integrate REST APIs with internal and third-party systems - Optimize application performance, memory usage, and reliability - Work with SQL databases and improve queries/data access layers - Debug production issues and provide long-term technical solutions - Refactor legacy code while keeping applications stable - Collaborate with our team through code reviews and async communication Stack you’ll use Backend & Frameworks - C# - .NET Framework - .NET 6 / .NET 8 - ASP.NET Core - Entity Framework Core - LINQ - REST API development - Background services Desktop Development - WPF - WinForms - Windows desktop applications - MVVM architecture - UI performance optimization - Multi-threading and asynchronous programming Databases - SQL Server - PostgreSQL - SQLite - Database design - Query optimization Tools & Process - Visual Studio - Git / GitHub - CI/CD workflows - Unit testing - Code reviews - Agile development process Must-haves - Strong professional experience with C# and the .NET ecosystem - Experience building production desktop applications - Solid understanding of object-oriented programming and software design patterns - Experience working with databases and APIs - Ability to understand and improve existing codebases - Strong debugging and problem-solving skills - Good written and spoken English communication - Ability to work independently and provide regular updates Nice-to-haves - Experience modernizing legacy .NET applications - Experience with large-scale business software - Knowledge of cloud services (Azure/AWS) - Experience with hardware integrations or system-level applications - Familiarity with automated testing practices - Experience building SaaS products Engagement details - Hourly contract - $20/hour - Long-term ongoing project - 20-30 hrs/week initially, with potential to increase - Remote worldwide - Flexible working hours Why this role - Long-term partnership instead of short-term tasks - Work on real production software used by customers - Opportunity to influence technical decisions - Variety of challenging engineering problems - Stable ongoing workload To apply, please include - A short introduction about your C#/.NET experience - Examples of desktop or backend applications you have built - Your experience with WPF, WinForms, or ASP.NET Core - Your weekly availability and start date We’re looking for a developer who wants to become part of the team and grow with us. This is not a one-time project — we’re looking for someone reliable for ongoing development.